Water flows indifferently east or west, says the Chinese philosopher Mencius. It does not flow indifferently up or down.

In many arid parts of the world, but especially the arid American West, Mencius’s axiom has a corollary: Indifferent or not, water can be made to flow uphill toward money. Money brought pharaonic civil-engineering programs like the Central Arizona Project and the All-American Canal to the desert; money brought the water that made boom towns of Phoenix and Las Vegas, metropolises that continue to grow even with a lingering economic downturn. And that money, once broadly distributed among farms, ranches, mines, and towns, is now increasingly concentrated in the cities of the West, lending the decades-long struggle over water rights a new dimension: the metropolis versus the countryside.

Irrigation canal near Coolidge, Arizona. (c) Gregory McNamee

Nowhere is this division more acute than Southern California, a lush land reclaimed from the Mojave Desert by the liberal application of both money and water. That reclamation was the work of boosters like Joseph B. Lippincott, a developer who helped convince Theodore Roosevelt to create the National Reclamation Act, and Frederick Eaton, a sometime politician who had previously been a farmer in Owens Valley, 200 miles north of Los Angeles.

Eaton may not have been especially adept at business or politics, but he had a clear view of the future. Southern California, he argued, could not grow without a steady supply of water. That water was to be found in Owens Valley, he said, in quantities “adequate for any requirement Los Angeles may ever have.” Water czar William Mulholland concurred, and in 1903 he looked north to Owens Valley to acquire water rights and secure territory for a great gravity canal. A decade later, Owens Valley water was spilling down the new Los Angeles Aqueduct to the city.

Yet Owens Valley was not enough “for any requirement Los Angeles may ever have.” Seventy years ago, in 1941, the aqueduct was extended to hauntingly beautiful Mono Lake, a destructive act that John Hart chronicles in his book Storm Over Mono. Mono Lake’s water fueled the growth of Los Angeles for a while, but it, too, was not enough, and Los Angeles pressed neighboring states for ever greater shares of the Colorado River.

In recent years the thirsty metropolises of the West have turned their attention closer to home, buying up farmland for water rights. The consequent decline of agriculture, which once used 90 percent of the available water throughout the arid West, will at least in theory enable Southern California, for one, to grow by scarcely imaginable leaps as fields are put out of production. Planners have projected that California’s population will reach 45 million sometime before the midcentury. If present trends of growth continue, by 2090 the number could be a staggering 300 million. And this in a time when water shortages are expected to become the norm.

Without agriculture, California has sufficient water to fuel such growth; it’s a mere problem of trading fresh lettuce and avocados for an endless strip mall stretching from Blythe to Seal Beach, from Eureka to El Centro. A similar pattern holds for the rest of the arid West: Futurists predict, for instance, that Arizona, now with about 6 million residents, can grow to a population of 25 million if agricultural water can be reallocated to municipal use. Cities like El Paso and Albuquerque, Sierra Vista and Elko are booming, and as what Wallace Stegner called the “oasis civilization” of the West becomes increasingly urbanized, the battle over water rights will increasingly favor the cities, where political power resides.

There is no level playing field in that struggle. The legal practice of “negotiated settlement,” an attempt at establishing parity, requires that all contending interests come together to bargain for water rights. In the case of the Truckee River of Nevada, whose water has long been in bitter contest, those parties include the states of Nevada and California, the cities of Reno and Sparks, American Indian tribes, utilities, environmentalists, and dozens of federal agencies and private interests. And farmers, too, although the farmers of the Fallon irrigation district, now but one voice among many, have found that their influence has diminished—and that their allocation of the Truckee’s water has decreased. “Now I know how the Indians felt,” one farmer told Nevada environmental journalist Brad Summerhill. “But the Indians’ own government didn’t do it to them.”

Will the desert be farmland, or will it be metropolis? In that question, which defines the long ongoing debate, there is no allowance for the desert as it is.

“Because we’re humans, it’s logical to look at nature for food, for cures,” Ann Zwinger, the Western nature writer, once observed. “But we must also recognize there are less easily identifiable values that lie in another dimension, a worth that is more, much more, than what is obvious.” The North American desert’s intangible worth is obvious to many who live there, but even that recognition will likely not soon resolve the fierce water wars that rage within its fiercely arid confines.

For a cinematic view of the water wars of the West, inspired by the history of Owens Valley, see Roman Polanski’s iconic 1974 film Chinatown, which never grows old. For a more distant take on water and its value, see the 2008 Turkish film Absurdistan, a lively update of the Lysistrata.